Update to Debian 6.0.7 and move ISO

This link http://cdimage.debian.org/debian-cd/6.0.6/amd64/iso-cd/debian-6.0.6-amd64-netinst.iso does not exist anymore. You can still find the iso from dodgy sources like http://www.ulozto.net/xxUwm44/debian-6-0-6-amd64-netinst-iso or on some archives, if you are lucky.

Officially, you find old cds with debian in http://cdimage.debian.org/cdimage/archive/
but then, the jigdo format is used (on mac, you can install jigdo with `brew install jigdo`)

I propose to copy the ISO from somewhere, cross-check it's md5 and copy it to a place we own, such as s3 or lion


Also, 6.0.7 would be the last version for squeeze. I propose not to update to 6.0.7 but wait for migration to wheezy.


@njam What do you think?